MTP (MPO) Fibre Networking Frequently Asked Questions

Frequently Asked Questions

For all Data Centre applications

Factory Terminated Fibre Cabling

Pre-terminated fibre infrastructure based around MPO connector, predominantly the MTP connector, enables data centre and network managers to simply add new fibre links to their network by clicking connectors together.

This has some immediate benefits

Installation is tool-less. Only Cleaning connectors is required

With such simple connections, any change can be carried out at a convenient time

MTP systems are modular. Each 24 fibre link can be added separately to all others

For those new to this type of networking, we answer some of the most commonly asked questions.

What is an MPO connector?

MPO is a generic name for multi-fibre push on. The majority of connectors have 12 fibres and they mate together in the same way as traditional LC, SC and ST connectors.

One brand of connector has become dominant – the MTP® fibre connector range of 12, 24 and 48 fibre connectors. These connectors are the footprint of an SC connector yet hold up to 24 fibres, thereby enabling high density connectivity.

High Density Cable

Most manufacturers use a similar construction of fibre microcore loose tube cable. This cable construction gives about 65% reduction in space when compared to traditional tight buffered or loose tube cables and similar reduction in weight.

The reduction in size and weight enables more cabling to be installed per cabinet / cable tray etc and thereby enables high density connectivity.

What makes up a high density solution?

High density networking is based on two components. One, being able to have concentrated port density. Two, being able to have large numbers of fibre cores connecting nodes of the network.

The MTP connector is the same size as a traditional SC connector. However, the MTP connector has 12 fibres to the SC’s one fibre. This 12 fold increase in density enables a much greater port density at any point on the network. There are also 24 fibre and 48 fibre connectors within the MTP range that are also the same size as an SC connector.

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Designing an MTP Network

The main difference to take into account when designing a network using a modular MTP solution over a traditional fibre solution is that the number of mated connector pairs in any fibre channel will increase. This increase in mated pairs increases the losses in the channel and these need to be understood in order to maintain the required performance.

MTP Fibre Channels

What distances can OM3 and OM4 run over using MTP solutions?

How can rack space be minimised?

What are the options to create longer fibre channels?
See our section on typical fibre channel, follow this link

How do I use MTP to reduce rack space requirement for cabling?

One of the main reasons for choosing an MTP solution is to increase the in-rack connectivity. This can be done in several ways: –
1. Use MTP-LC harnesses which connect directly to equipment from 1U MTP Panels (up to 576 fibres in 1U)
2. Use Zero U (side mounted) MTP Adaptor Plates
3. Use MTP direct equipment connections. Switch manufacturers, such as CISCO and Brocade, are now producing equipment with MTP connectivity.

How is the solution modular?

The starting point can be a 12 fibre link between 2 cassettes and 1 x 12 fibre trunk cable. This will give LC – LC (or SC- SC) connectivity for 12 fibre connections.

Cassettes are housed in either 1U sliding panels (each with the ability to hold 3 cassettes) or 3U fixed panels holding (1 to 14 cassettes).

However, most installations use 24 fibre cassettes are used as standard. Each of these takes one 24 fibre trunk cable with 2 MTP connectors on each end. If each 24 fibre link (two 24 fibre cassettes and one 24 fibre trunk) is called a unit then units can be added 1 at a time as the requirement grows.

Thereby giving a modular approach in 24 LC-LC connection steps. To minimise costs within a network, each unit can be chosen from either the M300 or M310 product series to ensure that the higher performance / lower loss M310 products are only used where necessary.

MTP adaptor plates can be added in exactly the same way. The 1U and the 3U housing for LGX cassettes can also be used to house the adaptor plates thereby enabling the minimum of rack space to be used.

What Installation skills are required?

The same principles apply whether you are installing a 24 fibre link either between 2 buildings, connecting an office floor to a comms room or creating hundreds of channels in a data centre.

There are 4 main principles to adhere to: –
1. Ensure that the link being created (distance and number of connector matings) meets the required standard.
2. Ensure that the polarity is managed across the link and in line with the network design
3. Ensure physical forces on the cables and connectors are managed by using strain relief on the cables to limit the tension in the cabling and maintain bend radii in both the cabling and patching accordng to the allowed specifications.
4. Follow the fibre connection procedures that you should use when connecting any type of fibre connectors together.

Is an OTDR required? In our view this is not essential as a test completed with a Light Source and Power Meter will establish the performance of the links.

Are any field terminations required?
The simple answer is NO.
All products are pre-terminated to enable an equipment to equipment link to be established without any on-site fibre terminations.
Flexibility is maintained by using MTP® adaptors to enable 2 trunk cables (or a trunk and a ruggedised fan-out) to be simply plugged together. LC or SC Cassettes are simply plugged into trunk cables using MTP® adaptors mounted in the rear of each cassette.

When is it sensible to use an MTP solution?

I don’t work much in data centres, are the products worth using in other situations?
The simple answer is YES. The products are becoming increasing used in standard office and commercial buildings (risers) as well as campus environments. The main reason for this uptake is that when a cost/benefit analysis is completed against using traditionally field terminated product sets, the pre-terminated MTP solutions start to come out on top.

Main benefits from pre-terminated include

the improved quality and consistency of the final links

The quality of field terminated fibre is always variable where as the pre-terminated MPO trunk cables, cassettes and fan-outs are constructed under controlled factory conditions and so give consistency high performance

the reduced time on site to complete the installation

Installation costs rise as time on site increases. It takes longer to set up a site termination and produce a high quality connection than to complete the same connection in a factory. It is easy to see that completing 48 fibre terminations (using any of the many types of field termination) in a site environment will take longer than in a properly equipped factory.

Access to site is becoming more restricted
Reducing on-site installation time is usually of benefit to the end-user. With pre-terminated fibre the time on site is dramatically reduced.

the reduction in skill required by installers

Fibre termination skills vary between individuals (in both factory and field situations). The site can have an impact on the ease of termination and hence the quality. People need to be properly trained and equipped to terminate fibre on site. This generally means that there is a shortage of available labour (with the right equipment in the right place) at the right time.

the reduction in cost of fibre termination and test equipment

Fibre termination tools / fusion splicers / connectors / test equipment / termination consumables – these all cost money and are constantly needing to be replenished. these tools are not being used all the time and are often in the wrong place at the wrong time requiring multiple kits to be purchased.

increased speed of installation

With our UK manufacturing and stock holding a large quanitity of fibre links can be delivered within days. Therefore, a fibre installation that could have previously taken weeks to complete can be done so in a greatly reduced timespan